ESSENTIALS OF PLANT 



secured, without chlorine 7.5 grams of seed. Apparently chlorine 

 was not essential. The seed grown in the absence of chlorine 

 were found, on analysis, to be nearly free from chlorine. These 

 seeds were used in another experiment in water culture as before, 

 with and without chlorine. With chlorine, they made seed ; with- 

 out chlorine, they failed to produce seed. Chlorine, therefore, 

 is essential. The seed used in the first series of experiments con- 



Fig. 2. Pot experiment showing soil deficient in nitrogen 

 and in phosphoric acid. Texas Station. 



tained a sufficient quantity of chlorine for the full development 

 of the plant, but those used in the second experiment did not. 



There are a number of instances in which apparently con- 

 tradictory results of different workers have been reconciled by 

 further investigation. 



The opposite results of the investigators referred to above are 

 due, in one case, to the presence of sufficient chlorine in the seed 

 used; in the other case, to insufficient chlorine in the seed. We 

 may conclude that chlorine is essential to the plant, but the min- 

 ute quantity required may be present in the seed. Chlorine is 



